1. Field of the Invention
The present disclosure relates to a vibration-reducing device and more particularly, to a vibration-reducing device for use with a scroll saw.
2. Description of the Related Art
Referring to FIG. 1, a conventional scroll saw 10 comprises a body 12, a U-frame 14, a worktable 16, a saw blade 18, an actuating device 20 and a fan-shaped member 22. The U-frame 14 is mounted to the body 12 and includes an upper arm 24 and a lower arm 26. The worktable 16 is mounted to the body 12 and is located between the upper arm 24 and lower arm 26 for supporting a workpiece (not shown). The saw blade 18 is mounted to the upper arm 24 and lower arm 26 and is passed through the worktable 16. The actuating device 20 includes a motor 28 and is mounted to the body 12 and is configured to synchronously drive the upper arm 24 and lower arm 26 to alternately move upwards and downwards to effect the movement in the up-down direction of the saw blade 18. The fan-shaped member 22 is configured to reduce the degree of vibration in the up-down, or otherwise generally vertical, direction caused during the operation of the conventional scroll saw 10.
Referring to FIG. 2 showing a vertical cross-sectional view taken along a line 1-1 of FIG. 1, the actuating device 20 further includes a shaft 30 and a block 32. The shaft 30 is firmly coupled with the block 32 and a top end of the fan-shaped member 22 is firmly coupled with the shaft 30. The conventional scroll saw 10 further includes a driving member 34. One end of the driving member 34 is pivotally connected to the block 32 with a pivot shaft 36, and the other end is pivotally connected to the lower arm 26. The pivot shaft 36 is also coupled with the block 32 and an axis 38 of the pivot shaft 36 is offset from an axis 40 of the shaft 30.
Referring to FIGS. 1 and 2, the motor 28 is configured to drive the shaft 30 to rotate. When the shaft 30 is rotated, the fan-shaped member 22 is driven to rotate and the pivot shaft 36 is driven to move circularly. The pivot shaft 36 drives the lower arm 26 via the driving member 34 to cause the U-frame 14 to move back and forth in the up-down direction, which leads the saw blade 18 to move upwards and downwards to cut the workpiece. The center-of-gravity position of the fan-shaped member 22 is opposite to the position of the axis 38 of the pivot shaft 36, so that when one of them is located above the axis 40 of the shaft 30 (in the up position), the other one is located below the axis 40 of the shaft 30 (in the down position), such that the movement in the up-down direction of the U-frame 14 is opposite to the up or down position of the fan-shaped member 22. By this way, the movement in the up-down direction of the fan-shaped member 22 is able to reduce the degree of vibration caused by the movement in the up-down direction of the U-frame 14. However, the movement in the left-right direction of the fan-shaped member 22 increases the degree of vibration in the left-right direction for the conventional scroll saw 10.
In order to solve the foregoing problem that the fan-shaped member 22 increases the degree of vibration in the left-right direction for the conventional scroll saw 10, another conventional vibration-reducing device 50 of a scroll saw is provided.
Referring to FIG. 3 showing an exploded view of the conventional vibration-reducing device 50 of the scroll saw, the conventional vibration-reducing device 50 of the scroll saw includes two fan-shaped members 52. The movements of the two fan-shaped members 52 are opposite, so the vibrations in the left-right direction caused respectively by the two fan-shaped members 52 may approximately offset each other.
However, for establishing good vibration reduction, the weight of each conventional fan-shaped member 22, 52 of the scroll saw and its position in the scroll saw should correspond to the weight of the U-frame 14 and also its position in the scroll saw. But when the conventional scroll saws are mass-produced, the weight and the position of the U-frame 14 in each conventional scroll saw cannot be ensured to be completely the same. Accordingly, in view of economic considerations, it is inconvenient and unworkable to specifically make a corresponding fan-shaped member 22, 52 for each conventional scroll saw 10.